Shanghai American School uses Atlas Rubicon and we are well into the process of documenting our curriculum.
We are currenlty focusing a lot of attention on our essential questions.

ISS also uses Atlas Rubicon. We are currently working with the trainers to get them to map across our new (very visual!) MYP unit planner as well as the POI for Elementary. They have been extremely good with back-up and we now use this as our main document server. Being on 2 campuses the web-based functionality has made our lives so much easier when it comes to collaborative planning and documentation of grade level work. We implemented it in August 2007 and are still ironing out some of the details but see it as a 5 year developmental process. Atlas are at most conferences and may be at EARCOS - worth checking if you have nothing in place but be aware it is not the only platform on the market.